JP2006028276A - Thermally conductive polycarbonate resin composition and molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polycarbonate resin composition excellent in thermal conductivity and molding processability and having little warpage of a molded product, and a molded body thereof.
SOLUTION: (C) Graphitized carbon fiber with respect to 100 parts by weight of a polycarbonate resin alloy having a weight ratio of 100: 1 to 100: 100 of (A) polycarbonate resin and (B) polyethylene resin. A graphite powder having a thermal conductivity in the length direction of 100 W / m · K or more, an average fiber diameter of 5 to 20 μm and less than 5 to 100 parts by weight of carbon fiber, and (D) an average particle diameter of 1 to 500 μm. A thermally conductive polycarbonate resin composition comprising 5 to 100 parts by weight or less of a body.
[Selection figure] None

Description

  The present invention relates to a polycarbonate resin composition having excellent thermal conductivity and molding processability, and less warping of a molded product, and a molded body thereof.

  Polycarbonate resins have balanced properties such as excellent impact resistance, heat resistance, and dimensional stability, such as electrical / electronic field, precision machine field, automobile field, security / medical field, food / miscellaneous field, etc. It is used for a wide range of applications. In particular, demand is growing in the OA field, electrical / electronic field, precision machine field, and automobile field.

  In these fields, most devices are equipped with components that generate heat, but in recent years, power consumption has increased along with higher performance of devices and components, and the amount of heat generated from components tends to increase. There is a concern that local high temperatures may cause troubles such as malfunctions. At present, the heat generated by using metal materials is diffused in the chassis, chassis, heat sink, etc., but the demand for replacement of these metal parts has increased by increasing the thermal conductivity of inexpensive resin materials. ing.

  As a method for imparting thermal conductivity to a resin material, many methods for mixing various thermal conductive fillers with a resin component have been reported. For example, Patent Document 1 discloses a thermoplastic resin having excellent thermal conductivity by a resin composition filled with both high thermal conductivity inorganic fibers and high thermal conductivity inorganic powder. However, in Patent Document 1, there is no example in which a polycarbonate resin is actually used as a thermoplastic resin, and vapor grown carbon fiber whiskers are used as highly thermally conductive inorganic fibers, but the fiber diameter is small. Since the aspect ratio is large, uniform dispersion in the resin is difficult, and sufficient thermal conductivity cannot be obtained due to fiber breakage during dispersion. In Patent Document 1, fluidity, warpage and dimensional stability of an injection molded product are not evaluated at all.

  Patent Document 2 describes a thermally conductive polymer material containing graphitized carbon fiber having a fiber diameter of 5 to 20 μm and an average particle diameter of 10 to 500 μm. However, in Patent Document 2, the main purpose is to increase the filling amount in the resin in order to obtain high thermal conductivity, and the types of polymer materials include silicone rubber, epoxy resin, thermoplastic elastomer, Polyacetal is only used as a thermoplastic resin, all of which are unsuitable for use as casings for OA, electrical / electronic parts, precision equipment, etc., in terms of strength and appearance. There is no intention to improve moldability, warpage of injection-molded products, and dimensional stability.

  Furthermore, Patent Document 3 describes a thermoplastic resin obtained by blending a heat conductive carbon fiber and graphite. Specifically, polyphenylene sulfide (PPS) is only used as the thermoplastic resin. Moreover, the total amount of carbon fiber and graphite used is very large, and there is no description about warpage of the molded product.

  Patent Document 4 describes a thermoplastic resin composition obtained by blending a thermoplastic resin with graphite and other inorganic fillers. Specifically, polyphenylene sulfide (PPS) is only used as the thermoplastic resin. Moreover, the total amount of carbon fiber and graphite used is very large, and there is no description about warpage of the molded product.

  Patent Document 5 describes a fiber-reinforced resin composition obtained by blending 30 parts by weight or more of a carbon fiber aggregate having a thermal conductivity of 400 W / m · K or more in a length direction with 100 parts by weight of a thermoplastic resin. Yes. However, there is only a specific example of blending with polybutylene terephthalate resin, there is no specific thermal conductivity, and there is actually a large blending amount of the carbon fiber aggregate, which is fluid. There is also no description about warping of molded products.

  Patent Document 6 describes a conductive resin composition comprising 95 to 50% by weight of a thermoplastic resin and 1 to 40% by weight of carbon fiber and 2 to 30% by weight of graphite. However, there was no specific description regarding thermal conductivity, and no mention was made regarding fluidity.

JP-A-8-283456 JP 2002-88250 A JP 2003-49081 A JP 2003-138136 A JP 2000-143826 A JP-A-10-237316

  An object of the present invention is to provide a polycarbonate-based resin composition and a molded body thereof which are excellent in thermal conductivity and molding processability and have little warpage of a molded product.

  As a result of intensive studies in order to solve the above problems, the present inventors have added a specific amount of specific heat conductive carbon fiber and graphite powder to an alloy of polycarbonate resin and polyethylene resin. The inventors have found that a resin composition excellent in conductivity and molding processability and having little warpage of a molded product and a molded product thereof can be obtained, and the present invention has been achieved.

  That is, the present invention relates to (C) graphitized carbon fiber with respect to 100 parts by weight of a polycarbonate resin alloy having a weight ratio of 100: 1 to 100 of (A) polycarbonate resin and (B) polyethylene resin. A graphite powder having a thermal conductivity in the length direction of 100 W / m · K or more, an average fiber diameter of 5 to 20 μm and less than 5 to 100 parts by weight of carbon fiber, and (D) an average particle diameter of 1 to 500 μm. 5 to 100 parts by weight or less containing a thermally conductive polycarbonate resin composition and a molded article characterized by molding the thermally conductive polycarbonate resin composition, The present invention relates to a molded body useful as a housing for OA, electrical / electronic parts, and precision equipment parts.

  The polycarbonate-based resin composition of the present invention is a polycarbonate-based resin composition that has excellent thermal conductivity and molding processability, and has little warping of a molded product, and has great industrial utility, such as OA equipment, electrical and electronic equipment, precision It is useful in many fields such as equipment parts and housings.

The present invention will be described in detail below.
The (A) polycarbonate resin used in the present invention is a polycarbonate resin alone or an alloy (mixture) of a polycarbonate resin and another thermoplastic resin (except a polyethylene resin). In the case of the alloy, the polycarbonate resin The other thermoplastic resin is contained in a proportion of 100 parts by weight or less, preferably 70 parts by weight or less with respect to 100 parts by weight. The other thermoplastic resin is preferably a thermoplastic polyester resin, more preferably a polybutylene terephthalate resin or a polyethylene terephthalate resin.

  As the polycarbonate resin used in the present invention, aromatic polycarbonate, aliphatic polycarbonate, and aromatic-aliphatic polycarbonate can be used, and among them, aromatic polycarbonate is preferable. The aromatic polycarbonate resin is a thermoplastic aromatic polycarbonate polymer or copolymer produced by reacting an aromatic dihydroxy compound with phosgene or a diester of carbonic acid.

  Examples of the aromatic dihydroxy compound include 2,2-bis (4-hydroxyphenyl) propane (= bisphenol A), tetramethylbisphenol A, bis (4-hydroxyphenyl) -P-diisopropylbenzene, hydroquinone, resorcinol, 4, 4-dihydroxydiphenyl etc. are mentioned, Preferably bisphenol A is mentioned. Furthermore, for the purpose of further enhancing the flame retardancy, a compound in which one or more tetraalkylphosphonium sulfonates are bonded to the above aromatic dihydroxy compound, or a polymer or oligomer having a siloxane structure and containing both terminal phenolic OH groups is used. Can do.

  The aromatic polycarbonate resin used in the present invention is preferably a polycarbonate resin derived from 2,2-bis (4-hydroxyphenyl) propane, or 2,2-bis (4-hydroxyphenyl) propane and other aromatics. And a polycarbonate copolymer derived from an aromatic dihydroxy compound. Further, two or more kinds of polycarbonate resins may be used in combination.

  The molecular weight of the polycarbonate resin is a viscosity average molecular weight converted from the solution viscosity measured at a temperature of 25 ° C. using methylene chloride as a solvent, and is in the range of 14,000 to 30,000, preferably 15,000 to 28. 16,000, more preferably 16,000-26,000. If the viscosity average molecular weight is less than 14,000, the mechanical strength is insufficient, and if it exceeds 30,000, the moldability tends to be difficult, which is not preferable.

  The method for producing such an aromatic polycarbonate resin is not limited, and the aromatic polycarbonate resin can be produced by a phosgene method (interfacial polymerization method), a melting method (transesterification method), or the like. Furthermore, the aromatic polycarbonate resin which adjusted the amount of OH groups of the terminal group manufactured by the melting method can be used.

  Furthermore, as the aromatic polycarbonate resin of the present invention, not only virgin raw materials but also aromatic polycarbonate resins regenerated from used products, so-called material recycled aromatic polycarbonate resins can be used. Used products include optical recording media such as optical disks, light guide plates, automobile window glass and automobile headlamp lenses, vehicle transparent members such as windshields, containers such as water bottles, glasses lenses, soundproof walls and glass windows, waves A building member such as a plate is preferred. In addition, as the regenerated aromatic polycarbonate resin, non-conforming product, pulverized product obtained from sprue or runner, or pellets obtained by melting them can be used.

  In the present invention, when (A) the polycarbonate-based resin is an alloy, another preferable thermoplastic resin is a thermoplastic polyester resin, and a polybutylene terephthalate resin or a polyethylene terephthalate resin is more preferable.

  The polyethylene terephthalate resin (PET) may be produced by either a transesterification reaction between dimethyl terephthalate and ethylene glycol or a direct esterification reaction between terephthalic acid and ethylene glycol.

  In addition, the polybutylene terephthalate resin (PBT) is produced by either a DMT method by transesterification of dimethyl terephthalate and 1,4-butanediol, or a direct polymerization method of terephthalic acid and 1,4-butanediol. But it ’s okay.

  In either case of the PET or PBT, phthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, together with terephthalic acid or a dialkyl ester thereof during the polycondensation reaction Dibasic acids such as dialkyl esters, tribasic acids and the like, and dialkyl esters thereof can be used. The amount of these used is preferably in the range of 40 parts by weight or less with respect to 100 parts by weight of terephthalic acid or a dialkyl ester thereof.

  Similarly, during the polycondensation reaction, together with the ethylene glycol or 1,4-butanediol, other aliphatic glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, hexamethylene glycol, In addition to the group glycol, for example, other diols such as cyclohexanediol, cyclohexanedimethanol, xylene glycol, 2,2-bis (4-hydroxyphenyl) propane, glycerin, pentaerythritol, and polyhydric alcohols can be used in combination. The amount of these diols or polyhydric alcohols used is preferably in the range of 40 parts by weight or less with respect to 100 parts by weight of the aliphatic glycol. The amount of these used is preferably in the range of 40 parts by weight or less with respect to 100 parts by weight of terephthalic acid or a dialkyl ester thereof.

  The molecular weight of the polyester resin is an intrinsic viscosity measured at 30 ° C. in a mixed solvent of phenol and tetrachloroethane (weight ratio = 50/50), preferably 0.5 to 1.8, and more preferably 0. .7 to 1.5.

  Furthermore, as PET and PBT of the present invention, not only virgin raw materials but also PET and PBT regenerated from used products, so-called material recycled PET and PBT can be used. Spent products include mainly containers, films, sheets, fibers, etc., but more suitable are containers such as PET bottles. In addition, as recycled PET and PBT, non-conforming products, pulverized products obtained from sprues, runners, etc., or pellets obtained by melting them can be used.

  In the present invention, when the (A) polycarbonate resin is an alloy, it is preferably a polycarbonate resin alloy containing 10 to 70 parts by weight of a polybutylene terephthalate resin or a polyethylene terephthalate resin with respect to 100 parts by weight of the polycarbonate resin. is there.

  In the present invention, the polycarbonate resin and the polyethylene resin (B) are required to have a weight ratio of 100: 1 to 100: 100, preferably an alloy having a ratio of 100: 3 to 100: 30. Can be mentioned.

  The polyethylene resin means an ethylene polymer or copolymer having an ethylene chain in the molecular chain. Specifically, in addition to various polyethylenes represented by low density polyethylene (LDPE), high density polyethylene (HDPE), ultrahigh molecular weight polyethylene (UHMWPE), etc., random copolymers and block copolymers of ethylene-propylene, Copolymers of ethylene and α-olefins such as ethylene-butene random copolymers and block copolymers, copolymers of ethylene and unsaturated carboxylic esters such as ethylene-methacrylate and ethylene-butyl acrylate, ethylene -Copolymers of ethylene and aliphatic vinyl such as vinyl acetate.

  In the present invention, (C) graphitized carbon fiber uses less than 5 to 100 parts by weight of carbon fiber having a thermal conductivity in the length direction of 100 W / m · K or more and a fiber average diameter of 5 to 20 μm. is required. The carbon fiber preferably has a thermal conductivity in the length direction of 400 W / m · K or more.

  When the thermal conductivity of (C) is out of the above range, sufficient thermal conductivity cannot be obtained at a low filling rate as in the present invention. The carbon fibers used in the present invention are converged at a bulk density of 450 to 800 g / l, for example, carbon short fibers (chopped strands) usually cut to 2 to 20 mm as described in JP-A No. 2000-143826. Thus, a carbon short fiber converging body which is then graphitized can be mentioned. The carbon short fiber converging body is obtained by converging carbon fibers with a sizing agent, cutting to a predetermined length, and graphitizing to reduce the content of the sizing agent to 0.1% by weight or less. It is. Examples of the conditions for the graphitization treatment include a method of heating at 2800 ° C. to 3300 ° C. in an inert gas atmosphere. As another method, continuous fibers (rovings) can be graphitized and then cut into a predetermined length for use. The diameter of the carbon fiber is preferably 5 to 20 μm, and if it is less than 5 μm, it tends to cause problems such as a decrease in thermal conductivity when the polycarbonate resin is mixed and filled, and warpage becomes large. Stability is reduced and good appearance is difficult to achieve. Moreover, when there is more content of a sizing agent than 0.1 weight%, it will cause the fall of thermal conductivity. The compounding amount of the carbon fiber is 5 to 100 parts by weight, and if it is more than this, molding processability and dimensional stability are lowered, and warpage is increased. Further, when the blending amount is less than 5 parts by weight, sufficient thermal conductivity cannot be obtained. The blending amount is preferably less than 5 to 40 parts by weight, more preferably less than 10 to 40 parts by weight, and still more preferably 15 to 35 parts by weight.

In the present invention, it is necessary to use (D) 5 to 100 parts by weight of graphite powder having an average particle diameter of 1 to 500 μm in order to improve thermal conductivity and moldability and reduce warpage. When the average particle size of the component (D) exceeds 500 μm, or when the content exceeds 100 parts by weight, molding processability decreases. Even if the average particle size of the component (D) is less than 1 μm, it is difficult to handle such as being scattered during compounding, and it is difficult to uniformly disperse it in the resin. Since the (D) graphite powder usually has a thermal conductivity of 10 W / m · K or more, when the amount of the carbon fiber (C) is small, the amount of the graphite powder (D) is relatively low. A large amount is appropriately adjusted so that a predetermined thermal conductivity is obtained. As a compounding quantity of this (D), Preferably it is 5-100 weight part or less, More preferably, it is 10-80 weight part.
Moreover, as a total amount of (C) carbon fiber and (D) graphite powder, it is preferable to mix | blend 150 weight part or less with respect to 100 weight part of the alloy of (A) resin and (B) resin.

In the present invention, a flame retardant can be used to impart flame retardancy. The flame retardant is not particularly limited as long as it improves the flame retardancy of the composition, but a phosphoric acid ester compound, an arikari metal organic sulfonic acid metal salt, and a silicone compound are preferable.
As a phosphoric acid ester compound used by this invention, the compound shown by following formula (1) is preferable, for example.

（式中、Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４は互いに独立して、置換されていても良いアリール基を示し、Ｘは他に置換基を有していても良い２価の芳香族基を示す。ｎは０〜５の数を示す。）
上記式（１）においてＲ_１〜Ｒ_４で示されるアリール基としては、フェニル基、ナフチル基等が挙げられる。またＸで示される２価の芳香族基としては、フェニレン基、ナフチレン基や、例えばビスフェノールから誘導される基等が挙げられる。これらの置換基としては、アルキル基、アルコキシ基、ヒドロキシ基等が挙げられる。ｎが０の場合はリン酸エステルであり、ｎが０より大きい場合は縮合リン酸エステル（混合物を含む）である。

(In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each independently an aryl group which may be substituted, and X is a divalent aromatic which may have another substituent. And n represents a number of 0 to 5.)
In the above formula (1), examples of the aryl group represented by R _{1 to} R ₄ include a phenyl group and a naphthyl group. Examples of the divalent aromatic group represented by X include a phenylene group, a naphthylene group, and a group derived from, for example, bisphenol. Examples of these substituents include an alkyl group, an alkoxy group, and a hydroxy group. When n is 0, it is a phosphate ester, and when n is greater than 0, it is a condensed phosphate ester (including a mixture).

  Specific examples include bisphenol A bisphosphate, hydroquinone bisphosphate, resorcin bisphosphate, resorcinol-diphenyl phosphate, and substituted and condensates thereof. Examples of commercially available condensed phosphate compounds that can be suitably used as such components include, for example, “CR733S” (resorcinol bis (diphenyl phosphate)), “CR741” (bisphenol A bis ( Diphenyl phosphate)) and Asahi Denka Kogyo Co., Ltd. under the trade name “FP500” (resorcinol bis (dixylenyl phosphate)) and are readily available.

  The content of the phosphate ester flame retardant in the composition of the present invention is 1 to 50 parts by weight, preferably 3 to 40 parts per 100 parts by weight of (A) polycarbonate resin and (B) polyethylene resin alloy. Part by weight, particularly preferably 5 to 30 parts by weight. If the content of the phosphate ester flame retardant is less than 1 part by weight, the flame retardancy is insufficient, and if it exceeds 50 parts by weight, the heat resistance is excessively lowered.

  The alkali metal salt organic sulfonic acid metal salt used in the present invention is preferably an aliphatic sulfonic acid metal salt and an aromatic sulfonic acid metal salt. The metal constituting the organic sulfonic acid metal salt is preferably an alkali metal, alkaline earth metal, etc., and the alkali metal and alkaline earth metal include sodium, lithium, potassium, rubidium, cesium, beryllium, magnesium. , Calcium, strontium and barium. The organic sulfonic acid metal salt can also be used by mixing two or more kinds of salts. The aliphatic sulfonate used in the present invention is preferably a fluoroalkane-sulfonic acid metal salt, more preferably a perfluoroalkane-sulfonic acid metal salt. Preferred examples of the fluoroalkane-sulfonic acid metal salt include an alkali metal salt of fluoroalkane-sulfonic acid, an alkaline earth metal salt of fluoroalkane-sulfonic acid, and more preferably, a fluoroalkane having 4 to 8 carbon atoms. Examples include alkali metal salts and alkaline earth metal salts of alkanesulfonic acid.

Specific examples of the fluoroalkane-sulfonate include perfluorobutane-sodium sulfonate, potassium perfluorobutane-sulfonate, perfluoromethylbutane-sodium sulfonate, potassium perfluoromethylbutane-sulfonate, perfluorooctane- Examples thereof include sodium sulfonate, potassium perfluorooctane-sulfonate, and tetraethylammonium salt of perfluorobutane-sulfonate.
The aromatic sulfonic acid metal salt is preferably an aromatic sulfonic acid alkali metal salt, an aromatic sulfonic acid alkaline earth metal salt, an aromatic sulfone sulfonic acid alkali metal salt, an aromatic sulfone sulfonic acid alkaline earth metal salt, or the like. The aromatic sulfonesulfonic acid alkali metal salt and the aromatic sulfonesulfonic acid alkaline earth metal salt may be a polymer.

Specific examples of the aromatic sulfonic acid metal salt include 3,4-dichlorobenzenesulfonic acid sodium salt, 2,4,5-trichlorobenzenesulfonic acid sodium salt, benzenesulfonic acid sodium salt, and diphenylsulfone-3-sulfonic acid. Sodium salt, potassium salt of diphenylsulfone-3-sulfonic acid, sodium salt of 4,4′-dibromodiphenyl-sulfone-3-sulfonic acid, potassium salt of 4,4′-dibromodiphenyl-sulfone-3-sulfonic acid, Examples include calcium salt of 4-chloro-4′-nitrodiphenylsulfone-3-sulfonic acid, disodium salt of diphenylsulfone-3,3′-disulfonic acid, and dipotassium salt of diphenylsulfone-3,3′-disulfonic acid. It is done.
The compounding amount of the organic sulfonic acid metal salt is preferably 0.01 to 5 parts by weight, more preferably 0.02 to 3 parts by weight, with respect to 100 parts by weight of the alloy (A) polycarbonate resin and (B) polyethylene resin. Parts, particularly preferably 0.03 to 2 parts by weight. If the amount of the organic sulfonic acid metal salt is less than 0.01 parts by weight, sufficient flame retardancy is difficult to obtain, and if it exceeds 5 parts by weight, the thermal stability tends to be lowered.

  The silicone flame retardant used in the present invention is preferably a polyorganosiloxane having a linear or branched structure. The organic group possessed by the polyorganosiloxane includes hydrocarbons such as alkyl groups and substituted alkyl groups having 1 to 20 carbon atoms, vinyl and alkenyl groups, cycloalkyl groups, and aromatic hydrocarbon groups such as phenyl and benzyl. Chosen from. Even if polydiorganosiloxane does not contain a functional group, it may contain a functional group. In the case of a polydiorganosiloxane containing a functional group, the functional group is preferably a methacryl group, an alkoxy group or an epoxy group.

  Moreover, in this invention, a fluororesin can be included for the purpose of dripping prevention at the time of combustion. Here, the fluororesin is a polymer or copolymer containing a fluoroethylene structure, for example, a difluoroethylene polymer, a tetrafluoroethylene polymer, a tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene and fluorine. It is a copolymer with an ethylene monomer that does not contain. Polytetrafluoroethylene (PTFE) is preferable, and the average molecular weight is preferably 500,000 or more, and particularly preferably 500,000 to 10,000,000. As polytetrafluoroethylene that can be used in the present invention, all of the currently known types can be used.

In addition, when polytetrafluoroethylene having fibril forming ability is used, it is possible to impart higher melt dripping prevention property. Although there is no restriction | limiting in particular in the polytetrafluoroethylene (PTFE) which has a fibril formation ability, For example, what is classified into the type 3 in ASTM standard is mentioned. Specific examples thereof include, for example, Teflon (registered trademark) 6-J (manufactured by Mitsui DuPont Fluorochemical Co., Ltd.), Polyflon D-1, Polyflon F-103, Polyflon F201 (Daikin Industries, Ltd.), CD076 ( Asahi IC Fluoropolymers Co., Ltd.). Other than those classified as type 3 above, for example, Algoflon F5 (manufactured by Montefluos Co., Ltd.), polyflon MPA, polyflon FA-100 (manufactured by Daikin Industries, Ltd.) and the like can be mentioned.
These polytetrafluoroethylene (PTFE) may be used independently and may combine 2 or more types. Polytetrafluoroethylene (PTFE) having the fibril-forming ability as described above is prepared by, for example, using tetrafluoroethylene in an aqueous solvent in the presence of sodium, potassium, ammonium peroxydisulfide, at a pressure of 1 to 100 psi, and at a temperature of 0. It is obtained by polymerizing at ˜200 ° C., preferably 20˜100 ° C.

In the present invention, an elastomer may be included to improve impact strength.
As the elastomer, various known materials can be used and are not particularly limited, but a multilayer structure polymer is preferable. As a multilayer structure polymer, the thing containing an alkyl (meth) acrylate type polymer is mentioned, for example. These multi-layered polymers include, for example, polymers produced by continuous multi-stage seed polymerization in which a polymer in a previous stage is sequentially coated with a polymer in a subsequent stage, and a basic polymer. As a structure, it is a polymer having an outermost core layer made of a polymer compound that improves the adhesion between the inner core layer, which is a crosslinking component having a low glass transition temperature, and the matrix of the composition. A rubber component having a glass transition temperature of 0 ° C. or lower is selected as a component that forms the innermost core layer of these multilayer polymers. These rubber components include rubber components such as butadiene, rubber components such as styrene / butadiene, rubber components of alkyl (meth) acrylate polymers, polyorganosiloxane polymers and alkyl (meth) acrylate polymers. Or a rubber component using these in combination. Furthermore, examples of the component that forms the outermost core layer include an aromatic vinyl monomer, a non-aromatic monomer, or a copolymer of two or more thereof. Examples of the aromatic vinyl monomer include styrene, vinyl toluene, α-methyl styrene, monochloro styrene, dichloro styrene, bromo styrene, and the like. Of these, styrene is particularly preferably used. Examples of non-aromatic monomers include alkyl (meth) acrylates such as ethyl (meth) acrylate and butyl (meth) acrylate, vinyl cyanide such as acrylonitrile and methacrylonitrile, and vinylidene cyanide.

  In addition, the resin composition of the present invention is optionally provided with stabilizers such as ultraviolet absorbers and antioxidants, additives such as pigments, dyes, lubricants, mold release agents, glass fibers, glass flakes and the like. An agent or a reinforcing material such as whisker such as potassium titanate or aluminum borate can be added.

  As a method for obtaining the polycarbonate resin composition of the present invention, the above components are kneaded in various kneaders such as a uniaxial and multiaxial kneader, a Banbury mixer, a roll, a Brabender plastogram, etc., and then cooled and solidified. The above components are added to an appropriate solvent, for example, hydrocarbons such as hexane, heptane, benzene, toluene, xylene and their derivatives, and dissolved components, or dissolved components and insoluble components are suspended. The solution mixing method etc. which mix with are used. The melt-kneading method is preferable from the industrial cost, but is not limited thereto. In melt kneading, it is preferable to use a single-screw or twin-screw extruder.

In the present invention, the longer carbon fiber (C) is preferable in terms of thermal conductivity, improvement of warpage of the molded product, and the like. When such a long carbon fiber (C) is used, it is advisable to consider the operating conditions at the time of blending so that the long fibers are not broken and shortened when blended into the resin. For this purpose, for example, a method of feeding carbon fiber (C) and graphite powder (D) from the middle of the extruder during kneading is preferable. Among these, a method of feeding carbon fiber (C) and graphite powder (D) from the middle of the extruder using a twin screw extruder is preferable. By adopting such a method, it is possible to prevent the carbon fiber from being broken and shortened during kneading, and to achieve stable production.
Also, carbon fiber (C) is mixed in advance with a part of polycarbonate resin (A) or polyethylene resin (B) to be blended, and carbon fiber coated with part of the resin (A) or (B) Or preparing a masterbatch and then blending with the remaining resin. The resin used for the preparation of the coating or masterbatch may be an alloy of (A) and (B), but may be (A) alone or (B) alone. In the case of the alloys (A) and (B), an alloy having a composition different from the ratio of (A) and (B) of the target resin composition may be used.

  The method for obtaining a molded body using the resin composition of the present invention is not particularly limited, and a molding method generally used for thermoplastic resin compositions, for example, injection molding, hollow molding, extrusion molding, A molding method such as sheet molding, thermoforming, rotational molding, and lamination molding can be applied.

  The molded body of the present invention is widely used for OA equipment parts, electrical / electronic parts, and precision equipment parts, but is particularly suitable for OA equipment casings, electrical / electronic equipment casings, and the like. Examples include notebooks, mobile phones, PDAs, digital cameras, projectors, and other parts and housings.

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these ranges.
In the following examples, the following components were used.
(A) Resin (A-1) Polycarbonate resin: Poly-4,4-isopropylidenediphenyl carbonate, manufactured by Mitsubishi Engineering Plastics Co., Ltd., trade name: Iupilon (registered trademark) S-3000, viscosity average molecular weight 21,000 (Hereafter abbreviated as PC)
(A-2) Polyethylene terephthalate resin: manufactured by Mitsubishi Chemical Corporation, trade name: Novapex registered trademark) GG500 (hereinafter abbreviated as PET)
(A-3) Polybutylene terephthalate resin: manufactured by Mitsubishi Engineering Plastics Co., Ltd., trade name: NOVADURAN (registered trademark) 5010 (hereinafter abbreviated as PBT)
(B-1) High density polyethylene resin: manufactured by Nippon Polyethylene Co., Ltd., trade name: Novatec (registered trademark) HD HF310 (hereinafter abbreviated as HDPE)
(B-2) Linear low density polyethylene resin: manufactured by Nippon Polyethylene Co., Ltd., trade name: Novatec (registered trademark) LL UF421 (hereinafter abbreviated as LLDPE)

(C-1) Carbon fiber: manufactured by Mitsubishi Chemical Industries, Ltd., trade name: DIALEAD (registered trademark) K223HG, fiber average diameter 10 μm, average length 6 mm, sizing agent content 0.0%, length direction Thermal conductivity of 540W / m · K
(C-2) Carbon fiber: manufactured by Mitsubishi Chemical Industrial Co., Ltd., trade name: DIALEAD (registered trademark) K223GM, fiber average diameter 10 μm, average length 6 mm, sizing agent content 6.2%, length direction Thermal conductivity of 20W / m · K (length direction)
(D-1) Graphite powder: scale-like graphite, manufactured by Nishimura Graphite Co., Ltd., trade name: PB-90, average particle size 26 μm
(D-2) Artificial graphite fine powder: Showa Denko K.K., trade name: UFG-30, average particle size 11 μm
Flame retardant: Phosphate ester compound: Resorcinol bis (dixylenyl phosphate), manufactured by Asahi Denka Kogyo Co., Ltd., trade name: FP500
Fluororesin: Polytetrafluoroethylene, manufactured by Daikin Industries, Ltd., trade name: Polyflon F-201L
Elastomer: (Butadiene & Styrene) Core / Acrylic Shell Multi-layer Structure Polymer, manufactured by Mitsubishi Rayon Co., Ltd., trade name: METABRENE E-901

Examples 1-5, Comparative Examples 1-4
(A) Polycarbonate resin prepared in the ratio shown in Table 1, (B) Polyethylene resin, flame retardant, fluororesin, and elastomer are mixed uniformly with a tumbler mixer, and then a twin-screw extruder (manufactured by Nippon Steel Works) , TEX30XCT, L / D = 42, barrel number 12), cylinder temperature 280 ° C., screw rotation speed 200 rpm, feed from barrel 1 to extruder, melt knead, and barrel 7 (C) carbon fiber and (D) The graphite powder was fed to the extruder at the ratio shown in Table 1 and melt kneaded to pelletize the resin composition.

  Next, from this resin composition pellet, using an automatic heat press machine (manufactured by Otake Machinery Co., Ltd., 380 square, 65 tons), the press temperature is 260 ° C., the remaining heat is 8 minutes, the press is 20 seconds, and the cooling is 2 minutes. A press-molded product was prepared, and the thermal conductivity was measured using a sample in which three molded products were stacked.

This molded product was evaluated by the following evaluation method, and the results are shown in Table 1.
[Evaluation methods]
(1) Thermal conductivity The thermal conductivity of the press-formed product was measured using a rapid thermal conductivity measuring device (Keotherm QTM-D3, manufactured by Kyoto Electronics Industry).
(2) Flow length Resin temperature (measured temperature of purge resin): 290 ° C., mold temperature: 80 ° C. using an injection molding machine (manufactured by Sumitomo Heavy Industries, Psycap M-2, clamping force 75T) The flow length was measured under the conditions of mold: 20 mm width × 1 mm thickness and injection pressure: 147 MPa.
(3) Sled Box-shaped test piece of 150 mm × 150 mm / height 20 mm / thickness 2 mm under conditions of cylinder temperature 280 ° C. and mold temperature 80 ° C. using an injection molding machine (manufactured by Toshiba Machine, mold clamping force 150T). Was molded. Next, the warpage of the top surface of the test piece was measured using a three-dimensional measuring machine manufactured by Mitutoyo Corporation. The measurement was performed at 15 points at 10 mm intervals along the center line of the top surface, and the maximum amount of depression from the reference line connecting both ends was defined as a warp.
(4) Flame retardance According to the test method shown in UL-94 “Flame Test for Material Classification” (hereinafter referred to as UL-94) of Underwriters Laboratories, Inc. The test piece was tested, and based on the result, it was evaluated to any one of UL-94 standard V-0, V-1 and V-2. The grade criteria for each V for UL-94 are outlined below.
(i) V-0: Combustion time after flame contact for 10 seconds is 10 seconds or less, total combustion time of 5 tubes is 50 seconds or less, and all test pieces do not drop a particulate flame that ignites absorbent cotton.
(ii) V-1: Combustion time after flame contact for 10 seconds is 30 seconds or less, 5 total combustion times are 250 seconds or less, and all test specimens do not drop fine flames that ignite absorbent cotton .
(iii) V-2: Combustion time after flame contact for 10 seconds is 30 seconds or less, 5 total combustion times are 250 seconds or less, and absorbent cotton is ignited from the particulate flame dropped from these test pieces.
(iv) NG: It did not correspond to any of the above burning times and continued to burn.

Claims (6)

(C) Carbon fiber formed by graphitization with respect to 100 parts by weight of a polycarbonate resin alloy having a weight ratio of 100: 1 to 100: 100 of (A) polycarbonate resin and (B) polyethylene resin, 5 to less than 100 parts by weight of carbon fiber having a thermal conductivity of 100 W / m · K or more in the length direction and an average fiber diameter of 5 to 20 μm, and (D) a graphite powder 5 to 100 having an average particle diameter of 1 to 500 μm. A thermally conductive polycarbonate-based resin composition characterized by containing no more than parts by weight. (A) The polycarbonate-based resin is a polycarbonate-based resin alloy containing a polycarbonate resin alone or a ratio of 100 parts by weight or less of a polybutylene terephthalate resin or a polyethylene terephthalate resin to 100 parts by weight of the polycarbonate resin. 2. The heat conductive polycarbonate resin composition according to 1. The carbon fiber of (C) has a thermal conductivity in the length direction of 400 W / m · K or more, and the thermally conductive polycarbonate resin composition according to claim 1. The total amount of the component (C) and the component (D) is 150 parts by weight or less with respect to 100 parts by weight of the alloy of the (A) resin and the (B) resin. The heat conductive polycarbonate-type resin composition as described in claim | item. A molded article obtained by molding the thermally conductive polycarbonate resin composition according to any one of claims 1 to 4. The molded body according to claim 5, which is a housing for OA, electrical / electronic parts, precision equipment parts.